/*
 * OREKIT-X
 * Copyright 2002-2008 CS Communication & Systemes
 * 
 * Parts of this software package have been licensed to CS
 * Communication & Systemes (CS) under one or more contributor license
 * agreements.  See the NOTICE file distributed with this work for
 * additional information.
 *  
 * This is an experimental copy of OREKIT from www.orekit.org.
 * Please use the original OREKIT from orekit.org for normal work
 * unrelated to this research project.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you
 * may not use this file except in compliance with the License.  You
 * may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
 * implied.  See the License for the specific language governing
 * permissions and limitations under the License.
 */
package ore;

import ore.errors.OrekitException;
import ore.time.AbsoluteDate;


/** 
 * Interface for celestial bodies like Sun, Moon and Solar System
 * planets.
 * 
 * @author Luc Maisonobe
 * @see ore.bodies.SolarSystemBody
 */
public interface CelestialBody
    extends java.io.Serializable
{

    /**
     * Get the {@link PositionVelocity} of the body in the selected frame.
     * 
     * @param date Current date
     * @param frame The frame where to define the position
     * 
     * @return Position/velocity of the body (m and m/s)
     * 
     * @exception OrekitException If position cannot be computed in given frame
     */
    public PositionVelocity getPositionVelocity(AbsoluteDate date, Frame frame)
        throws OrekitException;

    /**
     * The frame is always bound to the body center, and its axes have
     * a fixed orientation with respecto to other inertial frames.
     * 
     * @return An inertially oriented body-centered frame
     */
    public Frame getFrame();

    /** 
     * @return Attraction coefficient of the body
     * <i>(m<sup>3</sup>/s<sup>2</sup>)</i>
     */
    public double getGM();

}
